This invention relates to optical mirror systems and their applications in optical switches, optical crossconnects, optical add/drop multiplexers and variable optical attenuator systems.
Dense wavelength division multiplexing (DWDM) systems and all-optical networks are in rapid development to provide high-speed signal processing in their native optical form without the need for expensive and time delaying conversions. The require the use of optical switches and optical crossconnect devices to redirect light signals and facilitate switching. Optical add/drop multiplexers are also key components in optical networks to add and drop certain light channels. In addition, single and multi-channel variable optical attenuators (VOAs) have wide applications in fiber-optic communication systems, for example, in limiting and regulating the power in fibers, equalizing power levels of different wavelength channels in dense wavelength division multiplexed (DWDM) systems, flattening the gain of optical amplifiers, and balancing the signals in optical add/drop multiplexers (OADMs).
According to one aspect of the invention, an optical mirror system includes a substrate; a reflective assembly attached to the substrate; an actuating mechanism attached to the substrate; and a drawbridge assembly mechanically coupled to the reflective assembly where upon activation of the actuating mechanism, the reflective assembly moves between a first position in which the reflective assembly is in a non-reflective state and a second position in which the reflective assembly is in a reflective state.
One or more of the following features may also be included. The drawbridge assembly includes a holding plate; at least one drawing member having two ends, a first end fixedly attached to the substrate; and a biasing mechanism for mechanically coupling the holding plate to the reflective assembly, wherein the actuating mechanism causes the biasing mechanism to bend the reflective assembly. The holding plate mechanically supports the biasing mechanism and is connected to a second end of the at least one drawing member.
In certain embodiments, the reflective assembly includes a mounting plate and a vertical mirror mechanically coupled to the mounting plate. Further, the non-reflective state of the reflective assembly forms a non-inclined configuration of the drawbridge assembly maintained by a resting state of the biasing mechanism, and the reflective state of the reflective assembly forms an inclined configuration of the drawbridge assembly caused by the actuating mechanism and a non-resting state of the biasing mechanism.
As yet another feature, the biasing mechanism includes a flexible structure for shaping the reflective state and the non-reflective state of the optical assembly.
According to another aspect of the invention, an optical crossconnect system includes a light beam traveling along a path; at least one optical mirror system having a substrate, a reflective assembly attached to the substrate, and an actuating mechanism attached to the substrate. The optical crossconnect also includes a drawbridge assembly mechanically coupled to the reflective assembly where upon activation of the actuating mechanism, the reflective assembly moves between a first position in which the reflective assembly is in a non-reflective state and a second position in which the reflective assembly is in a reflective state.
The optical crossconnect further includes at least one output fiber for emitting the light beam; at least one input fiber for receiving the light beam, where the light beam passes through the optical system and the path of the light beam is determined by an reflective state and a non-reflective state of the optical mirror system.
One or more of the following features may also be included. The optical crossconnect system further includes an array of collimating lenses and an array of coupling lenses for signal coupling and collimation of the light beam.
In certain embodiments, the optical crossconnect system also includes a scalable configuration having a plurality of rows and columns.
As yet another feature, the drawbridge assembly of the optical mirror system includes a holding plate; at least one drawing member having two ends, a first end fixedly attached to the substrate; and a biasing mechanism for mechanically coupling the holding plate to the reflective assembly where the actuating mechanism causes the biasing mechanism to bend the reflective assembly.
Embodiments may have one or more of the following advantages.
In optical fiber crossconnect systems, optical mirrors having a drawbridge assembly provide superior benefits in switching.
The combination of MEMS and optical technologies utilizes existing miniaturization technologies to fabricate the optical mirror systems. The use of optical mirrors in optical crossconnect systems provides the advantages of compactness, low driving voltage and current, low power consumption, compatibility with existing IC processes, low insertion loss, and a higher switch time. Furthermore, their use eliminates the drawbacks of large size, wobbling, and mechanical instability.
In particular, the flexible configuration of the reflective and non-reflective states of the system maintains the vertical mirror in an uplifted position thereby minimizing mechanical failure in the reflective and non-reflective switching positions. Important benefits are also achieved by eliminating the movement of the drawbridge assembly. Optical switching is accomplished without movement of the fixed components attached to the substrate. Consequently, the optical mirror system requires no additional actuators, thus reducing the number of elements required.
Another benefit is the scalability of the optical crossconnect systems. Forming optical crossconnect systems of large arrays can be easily and efficiently achieved, providing low power consumption and lower switch time.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.